This invention relates to a passenger seat, or xe2x80x9cseating unitxe2x80x9d, such as an aircraft passenger seat, with a breakover assembly. By the term xe2x80x9cbreakoverxe2x80x9d is meant the ability of the seat back of the seating unit to pivot forwardly past its normal upright position under predefined circumstances to a position where the seat back rests adjacent the seat bottom.
Aircraft passenger seats must be designed and constructed according to government regulations and aircraft manufacturer specifications. Virtually every aspect of seat design is thus constrained by requirements imposed by safety, weight and expense considerations. Within these limits the seat must also be aesthetically pleasing, comfortable to the seat occupant, and functional for the seat occupant as well as airline maintenance, repair and cleaning crews.
Main cabin, or xe2x80x9ccoachxe2x80x9d class seats are typically constructed with a seat bottom chassis formed from two or more leg modules and section assembly modules joined together by several beam elements which connect the leg modules and section assembly modules in spaced-apart relation to each other, and collectively form a ladder frame assembly. A seat bottom unit is mounted on the ladder frame assembly. The seat bottom unit is usually stationary. A seat back unit is pivotally-mounted between two of the section assembly modules so that the angle of the seat back unit can be controlled for reasons of comfort, safety and passenger ingress and egress past the rear of the seat. Because of the relatively short pitch between rows of seats, the normal range of movement of the seat back unit is relatively small. The degree of rearward, recline movement is constrained by the position of the rearward row of seats and the requirement to leave the passenger seated behind a particular seat with sufficient room to enter and exit his own and use the meal tray. The degree of forward movement of the seat back unit is limited to a position where the passenger is in a forwardmost xe2x80x9cuprightxe2x80x9d position for take-off and landings, and for meal service.
Passenger seats are designed whereby the seat back unit will not move beyond these positions under normal circumstances. However, provision must also be made for the abnormal situation where severe G-force loads are directed against the seat back unit. In such cases, the seat back must be allowed to xe2x80x9cbreakoverxe2x80x9d in a controlled manner in order to minimize damage to the seat and injury to a rear-seated passenger who may be thrown against the seat back during an emergency event.
As used herein, xe2x80x9cnormalxe2x80x9d load refers to those loads which are normally applied to the seat back during normal use, and includes loads imposed by passengers pushing or leaning on the seat back unit during ingress and egress, and minor rear impacts such as may occur during hard landings or xe2x80x9cshortxe2x80x9d stops upon landing. As used herein, xe2x80x9cabnormalxe2x80x9d load refers to any load in excess of a normal load and as specified in government regulations or aircraft manufacturer specifications. These requirements are well-known to all aircraft seat manufacturers. In general, such abnormal loads may be in the range of 16 G""s.
Therefore, it is an object of the invention to provide a passenger seat with a breakover assembly which permits the seat back unit of the seat to xe2x80x9cbreakoverxe2x80x9d into a position against the seat bottom unit upon the occurrence of a specified abnormal G-force load event.
It is another object of the invention to provide a passenger seat with a breakover assembly which reduces damage to the seat during application of an abnormal load.
It is another object of the invention to provide a passenger seat with a breakover assembly which reduces injury to a passenger seated aft of the seat.
It is another object of the invention to provide a passenger seat with a breakover assembly which can be quickly and easily replaced after an abnormal G-force event.
It is another object of the invention to provide a passenger seat with a breakover assembly which does not interfere with normal seat use and operation.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a passenger seat having a seat back breakover assembly, comprising a seat bottom chassis including a plurality of leg modules and a plurality of section assembly modules. A plurality of beam elements carries the leg modules and section assembly modules in spaced-apart relation to each other to define a ladder frame assembly. A seat back unit is pivotally-mounted between two of the section assembly modules for permitting the angle of the seat back relative to the seat bottom chassis to be varied as desired by the passenger. A recline unit is provided for controlling movement of the seat back and locking the seat back in a desired recline position. A breakover assembly is provided for preventing movement of the seat back unit forwardly past an upright position during normal use and for permitting forward movement of the seat back past an upright position in response to a predetermined abnormal load applied in a forward direction. The breakover assembly includes a controlled deformation member having a bend in one end thereof and positioned intermediate one of the section assembly modules and the seat back unit. The bend of the deformation member captures therein an attachment member fixed to and movable forwardly and rearwardly in unison with the seat back unit. An end of the deformation member remote from the bend is restrained for restricted and controlled movement relative to the section assembly module. The deformation member has a resistance to deformation in response to a normal forwardly-applied force sufficient to prevent forward movement of the seat back unit beyond the upright position. The deformation member is deformable in response to an abnormal forwardly-applied force along its length whereby the bend in the deformation member is translated rearwardly along the length of the deformation member to thereby dissipate the abnormal force without damage to the seat back unit.
According to one preferred embodiment of the invention, the controlled deformation member comprises a steel wire.
According to another preferred embodiment of the invention, the deformation member is restrained in a quadrant assembly stationarily-mounted on the section assembly module.
According to yet another preferred embodiment of the invention, the deformation member has an enlarged head on the end thereof defining the bend, and further wherein the quadrant assembly includes an elongate slot therein for receiving the deformation member with an enlarged recess communicating with the slot and receiving and capturing the enlarged head of the deformation member for locking the enlarged head in a fixed stationary position relative to the section assembly module.
According to yet another preferred embodiment of the invention, the quadrant includes a shear recess therein for receiving a pin with a sacrificial, breakable bushing positioned thereon. The recess is dimensioned to allow the pin to pass out of the recess upon breakage of the bushing positioned thereon upon an initial phase of the abnormal forward movement of the seat back unit to provide initial resistance to the forward movement of the seat back unit.
According to yet another preferred embodiment of the invention, the quadrant includes an outer surface for supporting thereon the metallic wire rearwardly of the bend therein, and a retainer bracket for maintaining the metallic wire against the outer surface of the quadrant.
According to yet another preferred embodiment of the invention, the attachment member is positioned in the bend of the wire and comprises a roller mounted on a pin fixed to the seat back unit.
According to yet another preferred embodiment of the invention, the invention includes a fluid cylinder assembly pivotally-mounted by a first end thereof to a section assembly module of the seat and by an opposite second end thereof to the seat back unit. The cylinder assembly has a longitudinally-extending axis extending in alignment with the longitudinally-extending, generally vertical plane of the seat back. An actuator is positioned astride and operatively connected to the fluid cylinder adjacent one or the other of the first and second ends thereof. An occupant-activated seat back recline control is provided for maintaining the seat back in a normally-locked condition relative to the seat bottom chassis for permitting the occupant to release the normally-locked condition of the cylinder assembly by activating the seat back recline control to permit movement of the seat back to a desired position, and deactivating the seat back recline control to lock the seat back in the desired position.
According to yet another preferred embodiment of the invention, the retainer bracket is carried by and is movable with the second end of the fluid cylinder assembly.
According to yet another preferred embodiment of the invention, a passenger seat having a seat back breakover assembly is provided, and comprises a seat bottom chassis including a plurality of leg modules and a plurality of section assembly modules. A plurality of beam elements carries the leg modules and section assembly modules in spaced-apart relation to each other to define a ladder frame assembly. A seat back unit is pivotally-mounted between two of the section assembly modules for permitting the angle of the seat back relative to the seat bottom chassis to be varied as desired by the passenger. A recline unit is provided for controlling movement of the seat back and locking the seat back in a desired recline position. A breakover assembly is provided for movement of the seat back unit forwardly past an upright position during normal use and for permitting forward movement of the seat back past an upright position in response to a predetermined abnormal load applied in a forward direction thereto. The breakover assembly includes an elongate steel wire having a bend in one end thereof and positioned intermediate one of the section assembly modules and the seat back unit. The bend of the wire captures therein an roller fixed to and movable forwardly and rearwardly in unison with the seat back unit. An end of the wire remote from the bend is restrained for restricted and controlled movement relative to the section assembly module. The wire has a resistance to deformation in response to a normal forwardly-applied force sufficient to prevent forward movement of the seat back unit beyond the upright position. The wire is deformable in response to an abnormal forwardly-applied force along its length whereby the bend in the wire is translated rearwardly along the length of the wire to thereby dissipate the abnormal force without damage to the seat back unit.
According to yet another preferred embodiment of the invention, the wire is restrained in a quadrant assembly stationarily-mounted on the section assembly module.
According to yet another preferred embodiment of the invention, the wire has an enlarged head on the end thereof defining the bend. The quadrant assembly also includes an elongate slot for receiving the wire with an enlarged recess communicating with the slot and receiving and capturing the enlarged head of the wire for locking the enlarged head in a fixed stationary position relative to the section assembly module.
According to yet another preferred embodiment of the invention, the quadrant includes a shear recess therein for receiving a pin with a sacrificial, breakable bushing positioned thereon, the recess dimensioned to allow the pin to pass out of the recess upon breakage of the bushing positioned thereon upon an initial phase of the abnormal forward movement of the seat back unit to provide initial resistance to the forward movement of the seat back unit.
According to yet another preferred embodiment of the invention, the quadrant includes an outer surface for supporting thereon the metallic wire rearwardly of the bend therein, and a retainer bracket for maintaining the metallic wire against the outer surface of the quadrant.
According to yet another preferred embodiment of the invention a fluid cylinder assembly is provided and is pivotally-mounted by a first end thereof to a section assembly module of the seat and by an opposite second end thereof to the seat back unit. The cylinder assembly has a longitudinally-extending axis extending in alignment with the longitudinally-extending, generally vertical plane of the seat back. An actuator is positioned astride and operatively connected to the fluid cylinder adjacent one or the other of the first and second ends thereof. An occupant-activated seat back recline control is provided for maintaining the seat back in a normally-locked condition relative to the seat bottom chassis to permit the occupant to release the normally-locked condition of the cylinder assembly by activating the seat back recline control to thus permit movement of the seat back to a desired position and deactivating the seat back recline control to lock the seat back in the desired position.
An embodiment of the method according to the invention comprises preventing movement of a reclinable seat back unit of a passenger seat forwardly past an upright position during normal use and permitting forward movement of the seat back past an upright position into a breakover position in response to a predetermined abnormal load applied in a forward direction thereto. The method includes the steps of providing a controlled deformation member having a bend in one end thereof, positioning the deformation member intermediate a stationary section assembly module of the passenger seat and the seat back unit carried by the section assembly module, and capturing in the bend of the deformation member an attachment member fixed to and movable forwardly and rearwardly in unison with the seat back unit. An end of the deformation member remote from the bend is restrained for restricted and controlled movement relative to the section assembly module. The deformation member has a resistance to deformation in response to a normal forwardly-applied force sufficient to prevent forward movement of the seat back unit beyond the upright position. The deformation member has characteristics permitting deformation in response to an abnormal forwardly-applied force along its length whereby the bend in the deformation member is translated rearwardly along the length of the deformation member to thereby dissipate the abnormal force without damage to the seat back unit.
According to yet another preferred embodiment of the invention, the step of providing a deformation member comprises the step of providing a steel wire.
According to yet another preferred embodiment of the invention, the steel wire is a 0.235 inch 1018 grade wire.
According to yet another preferred embodiment of the invention, an attachment member is captured in the bend of the deformation member, and is fixed to and movable forwardly and rearwardly in unison with the seat back unit comprises the step of capturing a roller.
According to yet another preferred embodiment of the invention, the method includes the step of capturing an enlarged head formed on the bend end of the deformation member in a quadrant fixed to the section assembly module for securing the enlarged head in a stationary position relative to the section assembly module during deformation of the deformation member.